2x3と3x2の行列の内積

2x3_3x2.ipynb

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   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "[[1 2 3]\n",
      " [4 5 6]]\n",
      "(2, 3)\n"
     ]
    }
   ],
   "source": [
    "A = np.array([[1, 2, 3], [4, 5, 6]])\n",
    "print(A)\n",
    "A.shape"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
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     "text": [
      "[[1 2]\n",
      " [3 4]\n",
      " [5 6]]\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "(3, 2)"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "B = np.array([[1, 2], [3, 4], [5, 6]])\n",
    "print(B)\n",
    "B.shape"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "array([[22, 28],\n",
       "       [49, 64]])"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "AB = np.dot(A, B)\n",
    "print(AB)\n",
    "AB.shape"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[22, 28]\n",
      "[49, 64]\n"
     ]
    }
   ],
   "source": [
    "print(f'[{1 * 1 + 2 * 3 + 3 * 5}, {1 * 2 + 2 * 4 + 3 * 6}]')\n",
    "print(f'[{4 * 1 + 5 * 3 + 6 * 5}, {4 * 2 + 5 * 4 + 6 * 6}]')"
   ]
  }
 ],
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